Current regulator for electric lamps



March 18, 1930- C L: WECHELT 1,750,740

CURRENT REGULATOR FOR ELECTRIC LAMPS Fild May 12. 1928 7 2 Sheets-Sheet l INVENTOR. 6M4. 4/-

i.) A TTORNEY.

March 18, 1930. c. L. WEICHELT 1,750,740 I CURRENT REGULATOR FOR ELECTRIC LAMPS Filed May 12, 1928 2 Sheets-Sheet 2 INVENTOR.

2. ATTORNEY.

Patented Mar. 18, 1930 UNETED STATES PATENT. QFFIQE CARL L. WEICEELT, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO 'WIRT COM- IPANY, OF PHELADELPHIA, PENNSYLVANIA, A CORPORATION OF MAINE CURRENT REGULATOR Application filed May 12,

My present invention relates to attachments for incandescent lamps by means of which the flow of current to the filament may be regulated and the intensity or candle power of the light produced thereby controlled and it has for an object the produc tion of an improved device of this character by means of which the light may be dimmed or reduced to a greater or lesser extent.

A current reducing device, embodying my invention, includes a rheostat ring rotatable around the axis of a plug which is insertable in a standard lamp receiving socket, the rotationable movement of the ring being the means of regulating the light from full incandeseence to a low point of dimness. This broad feature, together with other improved features of construction of the device are disclosed in my co-pending application Serial An object of my present application is to provide a novel arrangement of the outer protective casing of the device whereby ample spacing is provided between the rheostat 3' ring and affording a circulation of air in contact with said ring which will serve to keep the latter from overheating and maintain the casing cool at all times. The invention further comprehends arranging on such type so of casing and rheostat cooperating stops which act when the ring is rotated to arrest its movement in opposite directions. \Vith this construction, these elements may be provided with very little manufacturing cost and may be readily concealed and so protected as to prevent their being tampered with.

A further object of the invention comprises simple and eltective means whereby the outer casing may be held in a fixed position on the stationa v parts or plug, thereby insuring the proper limitation of the rheostat movement and hence a permanent position of the stationary brushes relative to the contact elements on the movable rheostat.

A feature of the invention also comprises the attachment of a lamp shade holder to the bottom of the exterior casing of the device by correspondingly threading these members. A simplified form of attachment consists in inwardly hanging the bottom edge of the eas- FOR ELECTRIC LAMPS 1928. Serial No. 277,246.

ing in the form of a single thread capable of universal cooperation with the threads of the usual shade holder or gallery.

The invention will be more thoroughly understood with the aid of the description to follow in connection with the accompanying drawings in which the samereference characters designate like parts and in which:

Fig. l is an elevation of a lamp socket with device embodying the present invention interposed between the two.

Figs. 2 and 2 are front and bottom views pt the upper portion of the outer casing mem J91.

Figs. 3 and 3 are frontand bottom views of a. lower portion of the outer casing member.

Figs. l and are views of the preferred form of making the lower casing member with a single thread flange.

Figs. 5 and 5 are views of a modified form or making the lower casing member with a single threaded flange.

Fig. 6 is a vertical sectional view of the device showing the parts in assembled position.

Fig. 7 is a similar view on the line 7"7". Fig. 6.

Fi 8 is a bottom view of the device, with lower casing member removed, showing the cooperating stops on the casing rheostat.

Fig. 9 is a bottom view of the plug showing the spring contacts in place.

Fig. 10 is a horizontal sectional view looking downwardly in the plane indicated by the line 10"-10 of Fig. 6, the socket being removed from the plug and the spring wipers being in place.

Fig. 11 is a similar sectional View on the line 11 11 of Fig. 6, showing the means of locking the upper casing member to the insulating body.

A lamp reducer or dimmer constructed in accordance with my invention comprises plug and socket members 12 and 13, respectively, adapted to form a connection between an electric lamp 20 and the terminal socket oi an electric fixture 2%. It also embodies a tubular rheostat ring, composed of inner and outer shells 15 and 16 enclosing a resistance unitembedded in a mass of insulating material 18 having terminals 19, 20, 21, 22 and 23, interposed between the plug and socket members and a surrounding protective casing.

The plug 12, comprises an insulating body surrounded at one end by a threaded metalcasing 25 of a' length suitable to engage a standard threaded lamp socket, and a pin 26, tapped to receive a screw 29, extending through the body and forming the center contact of the plug. To prevent rotation of the pin 26, relative to the insulating body the pin is provided with two diametrically opposite extensions 3 (Fig. 7) fitting within the corresponding grooves formed at the upper end of the central aperture in the insulating body. F or reasons to be discussed later, the insulated body of the plug is preferably formed in two parts 27 and 28 held together by the screw 29 threaded into the pin 26. To prevent rotation of the parts 27 and 28 relative to each other, the upper part 27 is provided with a noncircular projection 30 which fits into a similarly shaped seat 1 in the lower member 28.

The threaded'shell 25 is held in fixed position on the plug by providing an aperture in its'bottom which fits over the projection 30 and engages the shoulders 32 and 33 at its opposite sides.

The lower surface of the member 8 is formed with a pair of diametrically disposer extensions 35 and 37 spaced apart to provide two alined slots or grooves a0 and 41 separated by a partition integral with the extensions. Extension 36 is semi-circular and extension 37 is of lesser width to provide more spacing between its arc'uate edges and the overall diameter of the member 28, the purpose of this spacing to be made apparent later. Projecting from these extensions is another pair of extensions 15 symmetrically arranged with respect to the slots c escribed above. These latter extensions 37 engage the sides of an aperture in the end of the socket shell 13 to prevent rotary movement of the plug relative to the socket, and the closed portion of said end rests on the faces of the extensions 36 and 37. In this position the parts are secured by means of tubular rivets 38 and 39 extending through the bottom of the socket 13, plug member 28, and into the bottom wall of the plug shell 25.

The center contact which is commonly as sociated with an electrical socket shell is represented herein in the form of a spring contact 50 having a finger portion extending into the slot 40, between the extensions 36 and 37 and a depending portion extending through the aperture in the bottom of the shell for contact with the center or end terminal of anincandescent lamp base.

The desired current reduction is produced by a rotatable rheostat having terminals which successively engage a stationary contact or wiper to complete a series circuit ineluding a source of potential and the lamp filament. The stationary contact arrangement comprises a pair of spring wipers 51 and 52 (Fig. 9) respectively on the member 28 partly encircling the extension 3? and having arms 43 and 44 respectively extending into the slotsO and 41 between the extensions 36 and 37. The arm as is attached to the plug member at the bottom of the slot 41 by the rivet l7 and is also held in place by, and thereby being in electrical connection with the center pin 29 of the plug, while the arm 43 lies beneath the center socket contact 50, which latter parts are held together and attached to the plug member at the bottom of the other slot 10 by the rivet 46.

It will be seen that by connecting the wipers in the manner described, a series circuit is established which includes the center pin 26, spring contact 52, a portion or" the resistance coil depending upon the rheostat terminals in engagement with the wipers 51 and 52, wiper 51, rivet 46, contact 50, the lamp filament, the shell 13, screws 38 and 39 and the plug shell 25.

In order to obtain the advantages of a sliding contact arrangement and produce a positive engagement between the moving and stationary contacts, it is preferable that the mechanical relation between the rheostat ring 14, the socket 13 and the plug member 28 with its wipers 51 and 52 be one which will insure a tree rotation of the ring in either direction and at the same time restrict movement of the ring in an axial direction to a minimum in that plane in which positive engagement of the wipers 51 and 52 by the terminals 19, 20, 21, 22 and 23 is obtained.

This object is accomplished by providing the edge ofthe bottom of the lamp socket shell 13 with a depressed annular shoulder 48 which is adapted to receive an inwardly extending flange 49 on the upper endof the inner rheostat shell 15 by which the ring 14 is supported. In assembling these parts, the socket 13 is placed within the rheostat ring with its bottom projecting withinthe flange 19, the rivets 38 and 39 being then secured in position.

The construction of the resistance ring and a form which has been found to be especially satisfactory is the one shown herein. Referring to the Figures 8 and 10, a number of arcuate contact bars, five being shown, as 19, 20, 21, 22 and 23 are arranged in alinement concentric to the axis of the ring with their upper ends exposed. The latter ends are bent outwardly to permit an increased surface of contact with the wipers. One of the end bars as 19 is sufiiciently longer than the other to permit it in one position of adjustmentto simultaneously engage both the wipers 51 and 52, and the latter it will be noticed in Fig. 9 have their free ends extending toward each other. The bottom edge of the outer shell 16 ber hastwo apertures in its side of the unit is flanged outwardly and one half of the circumference of this flanged edge as indicated at 60, is made ofgreater width than the remainder, so that the diametrically disposed ends of this wider portion serve as means for limiting the rotational movement of the rheostat ring, the functional operation of this limitation of movement to be made ap parent in what follows. The other features of construction of the resistance unit and the cylindrical winding of the resistance coils are substantially the same as and disclosed in my co-pending application Serial No. 98,171 and hence it is not deemed necessary to discuss these features herein.

Referring to Figures 1, 2, 2 3 and 3 the outer casing of the device consists of two members 1 and 2 having a telescoping connection and joined at their free ends by locking devices whichmay be readily detachable. The upper member has two longitudinal slots formed on the lower end of the side wall to provide flexibility and two outwardly struck shoulders adjacent the slots. The lower memwall which interlock with said shoulders. The upper casing member has an inturned flange at its upper end fitting over the upper end of the 1nsulating body 28 and engaging the bases of the symmetrically arranged cylindrical extensions of said body. The diameter of both members 1 and 2 is substantially greater than that of the insulating body 28 and is spaced a sufficient distance away from the outer shell 16 of the resistance unitto prevent its becoming heated by radiation therefrom and to provide ample spacing between the unit and the casing to permit a proper circulation of air currents in contact with the rheostat ring.

The lower member 2 is formed with an extension 5 of smaller diameter on its lower surface, which is threaded to engage the threads of a shade holder as illustrated in Fig. 1. WVithin the extension, an annular band of insulating material 4 is fitted, the latter surrounding the lower portion of the socket shell 13 for the purpose of protecting it. This band 4 is prevented from longitudinal movement by a plurality of ears punched at several points from the inner horizontal surface surrounding the extension 5, and flanged radially inwardly to provide sup porting shoulders 7 for the band. A cheaper if and preferred means of forming the extenment to facilitate the circulation of air with in the casing.

In Figs. 5 and 5 which show a modified construction of the lower casing member, the outer dimensional diameter of the device extends throughout the height of the bottom casing 2; the latters bottom edge flanges substantially inwardly to provide a single thread formed in the manner described above, for engagement with the shade holder and to provide ventilation holes 11 formed on the bottom flanging portion. With this arrangement the insulating band 4 is dispensed with.

Various means of rotating the rheostat ring 14 may be employed and in the drawings 1 have shown a cord or flexible chain 70 secured between its ends to a staple 65 carried by the shell 16 and leading therefrom in opposite directions through eyes 5656 formed on the wall of the upper casing memher 1 and transformin the vertical pull upon the cords to the necessary tension in a horizontal direction to rotate the rheostat ring. In the general form of device to which this invention relates, the desired limitation of the rotational movement of the rheostat ring is accomplished by means of two cars 62 formed by shearing two slits in the bottom edge of the casing member 1 and bending portions of the wall inwardly so to provide stops against which the ends of the flanged portion of the outer shell act when the ring is rotated.

The point of attachment of the staple and the location of the eyes 56-56 should be such as to give the proper lead for the cords '70 and the location of the ears 62 should hear such a relation to the contacts 19 to 28 that the successive engagement of the contacts 19 to 23 by spring contact 51 is permitted simultaneously with the engagement of contact 19 by spring contact 52. In the general form of the device, the rotational movement of the ring 14 will be limitedto approximately one quarter of a revolution by the flanged portion 60 contacting on its diametrically opposite ends with the ears '62. ll ith this'arrangement it will be noticed that the limiting means of the rheostat movement are simple in construction and yet possess a high degree of effectiveness; also they are confined within the casing, thereby preventing altering of the adjustment by possible tampering or rough handling, thereby increasing the life of the device.

It is obvious from the arrangement of parts described that the upper casing member 1 should have a certain fixed position relative to the insulating body 28 which holds the lamp socket shell 13 around which rotates the rheostat ring and this position should be permanently insured against any possible rotational movement of the casing. This object is accomplished in the present embodiment of the invention by providing 4 embossed points 9 on the upper end surface of the casing memberv 1 these points being disposed in two diametrically opposite sets, the spacing between the two points of each set being equal to the width of the slot 31 formed between the two extensions projecting from the upper surface of the insulating body 28. In this way, a flat rectangular strip 63 of suitable material can be inserted within the slot 31 between the lower surface of the slot and the lower surface of the non-circular projection 30 formed on the upper insulating body 27 after the casing member 1 is placed in position on the insulating body 28, the opposite ends of the strip 63 projecting over the top surface of the casing member 1 between the pairs of embossed points a. The strip 63 is held in place by the screw 29 passing therethrough at its center. With this arrangement it is readily seen that the embossed points a efiectively prevent rotation of the band respective to the casing and hence the band 63 coacting with the slot 81 and the embossed points l prevent rotation of the casing 1 relative to the insulating body 28 and the other stationary parts.

Upon rotation of the ring, such as by pulling one end or the other of chain 70, the contacts 20, 21, 22 and 23 are brought successively into engagement with the spring 51 while the longer contact 19 is maintained in engagement with the spring 52. An electrical circuit will be established through the pin 26 to the spring 51 and thence through one of the contacts 20, 21, 22 or 23 and a portion of the resistance unit to contact 19 and spring 52. Since the spring 52 is secured to the socket center spring 50, current then passes through spring 50, to the center terminal of the lamp, through the filament, and into the sheath of the lamp base and the socket 13; from the socketl3, the electrical circuit continues through the rivets 38 and 39 and into the shell 25, thereby completing a circuit including in series a resistance and the lamp filament. By rotating the rheostat ring to cause the bar 19 to engage both springs 51 and 52 the rheostat resistance unit will be short-circuited and the lamp will burn with full brilliancy. v

From the arrangement of parts described, it will be seen that the device comprises a simple construction of parts which may be easily assembled, in which the various members are maintained in rigid mechanical and electrical contact with each other, in which the rheostat ring may be easily rotated to produce a firm, positive engagement of the stationary contacts with the rotating contacts, and in which all electrically conducting members and the limiting means of the rheostat ring rotation are protected from possible injury by contact with extraneous articles. 7

in accordance with the provisions of the patent statutes the principle of the invention has been described, and illustrated by the protrayal of a structure which in practice ias proved to be a statisfactory commercial embodiment thereof, but it is desired to have it understood that the structure shown is merely illustrative, and the invention may be carried out in other ways.

What I claim is:

1. In an electric lamp attachment, a rotary rheostat ring and a protective casing form ing an annular air chamber around said rheostat ring, said casing having two cars formed thereon projecting into the chamber, and said ring comprising an outer tubular shell having a portion or" one of its edges flanged outwardly and forming stops cooperating with said ears to limit the rotational movement of the ring.

2. In an electric lamp attachment, a metallic shell adapted to form a socket for an lectric lamp, a rheostat ring rotatable around said shell and a protective casing affording an annular spacing between the ring and said casing, the latter having formed thereon two inwardly projecting lugs and the rheostat having shoulders cooperating with the lugs to limit the rotational movement of the ring, said casing comprising upper and lower horizontal inwardly projecting flanges provided with a plurality of ventilation openings.

3. in an electric lamp fixture comprising an insulating body having an extension on its upper surface of lesser diameter provided with a slot, a lamp socket shell secured to the lower surface of the body, a revolvable tubular rheostatring surrounding the shell, a cylindrical casing for said body, shell and ring, and having on its upper end an inward ly projecting flange surrounding said extension, four embossed points formed on said flange and disposed in two diametrically opposite sets,'the spacing between the two points of each set equalling the width of the slot between said extensions, cooperating stops on said casing and said ring to limit the rotary movement of the latter, and a flat rectangular member inserted within said slot, the opposite ends of this member projecting over said flange between the two sets of'embossed points. i

i. In acurrent reducing device for electric lamps, the combination with a circular insulating body the upper surface of which is formed with an extension slotted transversely and having a shoulder surrounding the extension,'a lamp socket and an adjustable rheostat supported on said body, a cylindrical casing enclosing the socket and rheostat forming an annular chamber around said rheostat and having an inwardly projecting flange supported on said shoulder, cooperating stops projecting from said casing and rheostat into said chamber to limit the rotary movement of the rheostat, an elongated member carried in said slot and arranged with its opposite ends overlying the flange on the casing and means for securing said member to the casing.

5. In a current reducer for electric lamps,

the combination with an insulating plug having a non-circular projection on its lower end, a metallic shell encircling the plug and having a bottom provided with an aperture fiting over the projection, an insulating body the upper surface of which is formed with two spaced extensions providing a slot between them and a surrounding shoulder, said noncircular projection being seated in said slot, of a cylindrical casing having an inwardly projecting flange at its upper end supported on said shoulder and having formed thereon pr-otuberances disposed in alinement with the walls of said slot, an elongated member lying in the slot and extending over the casing be tween the protuberances and a center pin extending through the plug, the elongated member and the insulating body, and a lamp socket and rheostat mounted on the insulating body within the casing.

6. A current reducing device for electric lamps comprising a lamp socket shell, a rheostat ring rotatable around said shell, said ring comprising an outer tubular shell having a portion of one of its edges flanged outwardly and forming stop shoulders, a casing for the device comprising upper and lower detachable members aflording an air chamber around the rheostat, one of said members having inwardly projecting ears cooperating with the stop shoulders to limit the rotary movement of the rheostat, both of said members having inwardly projecting perforated flanges at their upper and lower ends respectively, said lower member having a threaded tubular extension depending from its flange, adapted to receive and support a lamp shade holder.

7 In an electric lamp fixture, the combination with a body of insulating material and a lamp socket shell carried by said body, of a tubular rheostat rin carried by and rotatable around the shell, a casing carried by said body and forming an annular air chamber around the ring, said casing having formed thereon two inwardly projecting lugs and said ring comprising an outer metallic shell having a portion of one of its edges flanged outwardly so as to form stops cooperating with said lugs to limit the rotary movement of the rheostat.

CARL L. WEICHELT. 

